Apparatus for and process of classifying minerals.



n. H. mcHARDs APPARATUS FOR AND PROCESS 0F CLASSIFYING MINERALS.

Wl, uw mw i m fr w Patentd Feb n. H. RICHARDS.

APPARATUS FOR AND PROQESS 0F CLASSIFYING MINERALS.

APPLICATION FILED 1ULY25. lA907.

noBnnrH. RICHARDS, on BosToN, MASSACHUSETTS.

APPARATUS FOR AND PROCESS F CLASSIFYIN G MINERALS.

Specification of Letters Patent.

, Patented. Feb. e, 191e.

Application filed J u1y 25, 1907. Serial N o. 385,503.

To all 'whom t may concern:

Be it known that I, ROBERT HALLOWELL R101-maps, a citizen of the UnitedStates, re-

The invention is susceptible of somewhat varied embodiment, and in theaccompanying drawings I have illustrated two slightly different forms,both, however, embodying the same principles of construction and operation.

In said drawings: Figure 1 is a longitudinal sectional view of myimproved apparatus, on the type that I term the perforated platehindered settling classifier;

' Fig. 2, a top plan view of the same; Fig.

3, a transverse vertical section, on the line 3 3 of Figs. 1 and 2; Fig.4, a similar section on the line 1 4 of said figures; Fig. 5, a'longitudinal sectional view of my improved apparatus of the type that Iterm the constricted pipe hindered settling classifier; Fig. 6,` atransverse sectional view of the same on the line 6-6 of Fig. 5; andFig. 7,

i a top plan view of same.

In order to make clear the nature and scope of my present invention, dIwill first define or explain the settling act of mineral grains inwater.

There are two conditions under which sands or mineral grains of mixedsizes and of different specic gravities can and will settle in water,viz.:

First. Where the grains are entirely free from one another, eachassuming its natural rate and speed of settling, due to its size, y

weight, and shape. When, for example, mixed grains of quartz and galenaare allowed to Settle in water under these conditions, it is found thatthe grains of the lighter quartz, which settle at the same rate with theheavier galeria, have a diameter of (approximately) four times that ofthe latter. This is called classifying under free settling conditions.

Second. If, on the other hand, water be admitted through a smallaperture or series of apertures to the bottom of a vessel in whichavmass of grains of quartz and galena is resting, the rise of thecurrent of water through .the mass causes the quartz and galeria grainsto arrange themselves according to their ability to settle under suchconditions, and it is found that the grain of quartz that settles injuxtaposition with the grain. of galena has (approximately) six timesthe diameter of the latter. This method of classification is calledclassification under hindered settling conditions.

Among many ways-in which the hindered settling conditions may belcommercially utilized, two will be here described and illustrated.` Thetwo types of apparatus I designate as the perforated plate hinderedsettling classifier, and the constricted pipe hin- .deredsettling'classifier. These will bede'- scribed in the order named, itbeing observed, however, that in each the pressure' chamber is incommunication with the pocket by a reduced thoroughfare and theprincipleor mode of operation is the same in both, though details ofconstruction differ, andthe exact forms here shown are not necessary,vprovided the principle is maintained. This mode of operationconstitutes a process which is an inseparable part of the invention asembodied in the classifier of either type disclosed. Y

Referring to Figs.` 1 to 4,' inclusive, showing the'perforated plateconstruction, A indicates a flume or trough, having at one end a feedhopper, B, and provided with a lining comprising` a sole plate a andwall plates b, which lining is removable for the -purpose of renewalwhen worn. The se parts,may be of wood, metal, stone, or 1n fact of anysuitable material, iron being suitable for the linings At suitableintervals the bottom and sole plate. of the fiume or trough areinterrupted,v 'or provided with vertical openings c forming verticalpockets, extending transversely across them, as best seen in Figs. 1 and2. At that side of each opening o farthest from the feed hopper B thereisa dam or raised wall d, the several dams being shown ofprogreshowever, is not essential.

sively less height from the receiving toward the delivery end of theflume or -trough A, as will be seen upon referringtoFig. 1. This,Beneath the flume or trough A and bolted or otherwise made fast theretois a series of hutches or relatively narrow chambers C, which may becast or otherwise formed, and which are advisably made of the form shownby Figs.

l, 3 and 4. These hutches extend trans? versely across the under side ofthe flume and incline somewhat sharply downward toward one side, whereeach terminates in a circular spoutv or mouth c, which may bcconveniently filled by a wooden plug f, bored to receive an iron pipe g,in turn supplied witlraspigot-n, or the spigot may be directly appliedto the plug f. The inclined bottom wall of each hutch is preferably madeof semi-circular cross section better to insure drainage to the outlet.Each hutch is somewhat longer than the width of the flume or trough andextends beyond one lside thereof, vas seen in Figs. 3 and 4, and risingfrom the top of such projecting portion of each, is a water pipe D,communicating with a main E, and furnished with a regulating cock orvalve F, by which the supply of water can be regulated, or if need be,wholly cut 0E. That portion of the top wall of each hutch which standsimmediately under an opening 0 of the trough or tank A., is perforatedby orifices it, and at a point between the pipe D and the orifices thereis formed or placed a depending wall or apron z', seen in Fig. 4, whichlcauses the water entering by pipe D to first descend toward the lowerpart of the hutch and then to riseand pass with practical uniformity tothe several orifices of the series. This action is aided also by theinclination of the lower wall of the hutch. The orifices are ofcomparativelysmall diameter, so that the water rises through them injets of, greater or less intensity, tending to hinder or retard thesettling of the grains carried by the mixed water and sand flowingthrough the dunne and across the vertical pockets checked in sone degreeby the dams d. While the orifices are thus small enough to produce jetsyof strength sufficient to maintain the sands in a condition closelyresembling that of moving ,qucksan'd, they are yet large. enough topermit the heavier grains or particles to settle and pass down throughthe orifices, into the hutch beneath, and `to gravitate therein towardthe outlet. By properly adjusting the regulating valve of each branchpipe D, the action may be controlled with great nicety. Thesethoroughfares are also constricted, in form as compared to the Width ofthev bottom of the pocket as toboth modifications illustrated,

and if individual orifices are considered,

they are constricted in all horizontal dimentimers E heights of thedams, the diameter of the orices, the intensity of the jets, the crossarea and depth of hutches, and like details must be regulated or variedin accordancev with the minerals treated, andtheir size and condition.T'n some cases it may be found advantageous to make the dams ofincreasing height toward the delivery end of the flume.

Under the construction and arrangement of parts above set forth, thewater and sand or granular mineral matters are delivered into the hopperB, and flow along the Hume until .the first dam is reached, where theflow is in a measure checked and it is subi jected to the influence ofthe water jets rising through the orifices L and vertical pockets, themain current flowing on and over the various pockets c and dams al insuccession, and being acted upon by the water jets at each point. Theheavier particlesV fall through the orifices, those of greatest weightdescending into the first hutch, and the other hutches receiving insuccession particles or grains of progressively less weight.

The flume may be replaced by a tank, or, in' other words, may have apartition across its lower or delivery end, if desired, as in Figs. 5, 6and 7.

Tn Figs. ,5, 6 and 7 there is shown a construction in which the pockets,perforated plates and hutches are replaced by pipes or vcolumns, withconstrictions in them, the principle of operation remaining, however,the same. In these figures Af indicates a tank, the sides of whichconverge toward each other in the lower part, making the flume oftl-shape in cross section. The walls and sole or bottom plate will beprovided with replaceable linings, as before, and at suitable intervals`there are vertical openings c. Directly beneath each opening c there isplaced a vertical pipe or column. C, which will be made of cylindricalform, preferably. Fach pipe or-column is formed with a constriction h ata point somewhat below its top, which constriction may be produced byreducing or indenting the pipe, or by introducing a perforated plug, asmay .be found convenient, both constructions being shown in Fig. 5. Thevertical lopenings c' `and the interior of the pipes or columns C abovethe constrictions form deep vertical pockets. These vertical pocketshave their walls on the delivery side thereof of graded depth, thosenearest the inlet hopper being.. deepest.v This corresponds to thegraded heights of dam d in the first described structure, see Fig. fl.The lower end of each pipe or column is necked down or reduced indiameter in any convenient way, and is furnished witl'fa cock, gate orspigot g of any suitable type. At a point between the constriction z/and the lower en d of the pipe or column C', a pipe D opens into eachpipe or column,'as seen in Fig. 6, said pipes D in turn connecting witha water v main E', and being each provided with a regulating valve F,all essentially the same asunder the first described construction. Thetank A is in this case shown closed at its lower end, with an overflowat which the water and light floating matterspass off, and with a safetyspigot G, through which sands too heavy for the overflow and tooA lightfor the last regular spigot can escape. In this way the formation of ahurtful bank in the tank is prevented.

The principle or mode of operation of the two forms of apparatus isessentially the same as explained in connection with the perforatedplate construction of Figs. 1 to 4 inclusive, hence need not berestated.

lUnder both constructions itis possible to vary or regulate the actionin each hutch or v.column by opening the discharge spigot g,

or g to greater or less extent; but ordinarily it is preferred to effectthe regulation solely by the valves F and F. The heaviest material willbe segregated in the first or deepest pocket similarly to vthe action inthe first described structure where the heaviest material is segregatedin the first pocket from which delivery is guarded by the highest dam(l. A

The number-of hutches, columns or settling chambers may be increased ordiminished at will to agree with the number of separations' or grades ofmaterial wanted.

A cover-plate placed over any perforated plate or section of the screen,or a plug inserted in the top of any column will render the hutch orchamber below inoperative and prevent material from settling therein. lnsuch case the water supply of each s uch hutch or chamber will be cut0H'.

As in the case ofthe hutches C so with the columns C', the proportionswill depend somewhat upon the character of the minerals operated upon,the size and specific gravities of the particles, etc. No fixedproportions can be given, but the general proportions can be found bytrial. The area of the hutchv or the column must be sufliciently inexcess of the constriction so that quicksand conditions will exist inthe column, while at the same time the heavy grains are dischargingthrough the constrictions. If the constrictions arel too small the twoacts cannot take place together; if too large then free settling willtake the place ofhindered settling.

Havin g thus described my invention, what I claim is:

l. A classifier having. a pocket of substantially constant area in'horizontal cross-section throughout its entire depth, and having achamber below said pocket in communication therewith by'a thoroughfareboth concentrated and constricted with reference to at least onedimension of said pocket measured in a horizontal plane, wherebyquicksand conditions may bevmaintained in said pocket and a highvelocity of flow in said thoroughfare, a water inlet to said chamber,and a discharge from said chamber ,for heavier grains or particlespreviously passed through said thoroughfare.

2. A classifier having a pocket of substantially constant area inhorizontal cross-section through its entire depth, and having a 1chamber below said pocketin communication therewith by a thoroughfareboth concentrated and constricted with reference to one dimension onlyof said 4pocket measured in a horizontal plane, whereby quicksandconditions may be maintained in said pocket and a high velocity of flowin said thoroughfare, a water inlet to said chamber, and a dischargefrom said chamber for heavier grains or particles previously passedthrough said thoroughfare.

' 3. A classifier having a pocket of substantially constant area inhorizontal cross-section throughout its entire depth., and having achamber below said pocket, a plane perforated plate forming the bottomof said pocket and the top of said chamber, the perforation of saidplate forming a thoroughfare both concentrated and constricted withreference to at least one dimension of said pocket measured in ahorizontal plane, whereby quicksand conditions may be maintained in saidpocket and a high velocity of How in said thoroughfare, a water inlet toSaid chamber, and a discharge from said chamber for heavier grains orparticles prewhereby quicksand conditions may be maintained in saidpocket and a high velocity of flow in said thoroughfare, a water inletto said chamber, and a discharge from said chamber for heavier grains orparticles paeviously passed through said thoroughfare.

5. A flume, a series of pockets in the bottom of said flume andopeningdirectly therein, said pockets being of substantially constant area inhorizontal cross section throughout their entire depth, a series ofchambers in communication with said pockets by orifices passing fluidupwardly there- 'p by a single-thoroughfare in the length longitudinallyof the flume.

7. A classifier having a pocket of substantially constant area inhorizontal crosssection throughout its enti-re depth, said v pockethaving a wall prolonged to form a dam, means for passing across saidpocket material to be classified, and said classifier having a' chamberinccmmunication with said pocket by a thoroughfare passing fluidupwardly therethrough and heavier grains or particles downwardlytherethrough, and means for delivering fiuid to said chamber and heaviergrains or particles therefrom.

8. A classifier having a pocket and a chamber, a plane plate ordiaphragm between said pocket and said chamber, said plate having asingle thoroughfare therethrough constricted in all horizontaldimensions of said pocket, said thoroughfare being of size large enoughto pass the heaviest grains or particles admitted above same, and lmeansfor delivering fluid to said chamber and said grains or particlestherefrom.

9. A. classifier having a pocket with a fiat bottom, and having achamber below said pocket, an orifice constricted in all horizontaldimensions, forming a thoroughfare from said chamber through the bottomof said pocket, said orifice being of size small mysterie.

enough to produce jets of sufficient strength to maintain quick-sandconditions in said pocket and being of size large enough to pass theheaviest lgrains or particles admitted to said pocket, and means fordelivering fluid to said chamber and said grains or particles therefrom,whereby a separation from the raw product results of grains of differingspecific gravity diiering greatly in size.

10. A classifier having a pocket and a chamber, a plane plate ordiaphragm between said pocket and said chamber, said plate having asingle thoroughfare therethrough constricted in all horizontaldimensions of said pocket, said thoroughfare being of a size bearing thesame ratio to the diameter of the largest particles of heavier specificgravity admitted to said pocket, that the diameter'of those of lighterspecific gravity having the same settling characteristics bears to saidfirst-mentioned diameter, and means for delivering fluid to said chamberand said grains or particles therefrom.

11. lThe process of classifying materials differing substantially inspecific gravity, consisting in immersing said materials in a column ofliquid of `substantially uniform upward slow current flow, subjectingsaid immersed materials to the direct action of an upwardly directedconstricted jet of said liquid of quick current flow at the bottom ofsaid column, proportioning the velocities of said liquid so as tomaintainvquicksand conditions in saidA column, and collecting theheavier particles gravitating through said jet both of higher and lowerspecific gravity but differing materially in size.

ln testimony whereof lf have signed my name to this specification in thepresence of two subscribing witnesses. l

ROBERT H. RECHAR'DS.

Witnesses:

WALTER HUMPHREYS, J.. M. Coins'roon.

